1. Field of the Invention
The present invention related to sterring wheels for motor vehicles, more particularly, but without limitation, to passenger motor vehicles.
2. Prior Art
In order to reduce personal injuries resulting from most types of automobile accidents, seat belts were installed in passage vehicles for individuals driving and riding in the vehicle. Although the use of individual seat or safety belts did help reduce personal injuries in most types of automobile accidents, the driver of the vehicle and the passenger in the front seat of the vehicle were often thrust forward and injured, particularly in head-on impact accidents, when the vehicle comes to a sudden stop. Injury was suffered because the seat belt, even though properly used, failed to accord the necessary body restraint to guard against striking or impacting with the steering or the dash board, due to the close proximity of the driver to the steering wheel and the close proximity of the passenger to the dash board, respectively.
This lead to the use of the inflatable air bag, one of which was located in the hub of the steering wheel to protect the driver and another of which was located in the dash board, in front of the front passenger, to protect the front seat passenger. An example of an air bag located in the hub of the steering wheel of a motor vehicle is shown and described by Muraoka et al in U.S. Pat. No. 4,938,503 and an example of an air bag located in the dash board of a vehicle, in front of the front seat passenger, is shown and described by Pack, Jr. in U.S. Pat. No. 4,895,389.
In the use of an inflatable air bag to protect the driver from injury due to contact with the steering wheel, several issues became apparent. One issue was, where to mount the air bag. This was resolved by mounting the air bag in the hub area of the steering wheel. It then became apparent that a race would occur between air bag inflation and driver impact with the steering wheel. In this respect, inflation of the air bag had to be sufficiently fast to generate at a partial inflation of the bag in order to intercept the person of the driver before the thrust of the sudden stop, caused by the impact, drove the person of the driver to make unwanted contact with the steering wheel. To over come this problem, inflation of the air bag was given a head start by actuating the inflation in response to the impact, which actually precedes the sudden stop caused by the impact. This time advantage was accompanied by extremely rapid inflation of the air bag and in most cases the air bag is sufficiently inflated to intercept the person of the driver and protect the driver from unwanted contact with the steering wheel. However, in some cases, for example, where the person of the driver is in extremely close proximity to the rim and/or the spokes and/or hub of the steering wheel and/or the person, particularly the head of the driver, is offset from the expected normal path of expansion by inflation of the air bag, the inflating bag is not always successful in protectively intercepting the person of the driver. In some cases, particularly where the person of the driver is offset from the path of expansion of the inflating air bag, the driver has suffered abrasion by failing to make a solid contact with the inflating bag. These problems are addressed and solved by the present invention.
It also became apparent that when the air bag is mounted on the hub of the steering wheel, the steering wheel, which is normally composed of a rim or armature, several radial spokes and a hub, forms a cage with which the air bag comes in contact during inflation and the position or orientation of the cage influences the path of the expansion of the inflating bag. The present invention addresses the problem of using the cage to more advantageously direct the path of expansion of the inflating air bag so as to more directly intercept the person of the driver before the driver makes unwanted contact with the steering wheel.